VESS – VISUAL EVALUATION OF SOIL STRUCTURE

Research on soil structural quality and management concluded that soil structural quality was particularly vulnerable to compaction, which in turn reduced grass and grain yields. Further, soil structure and biological activity are particularly important in managing productivity within organic crop rotations because crops depend more on soil of good quality when common fertilisers and pesticides are eliminated.

VESS: has been developed by SRUC in partnership with the Universities of Aberdeen and Aarhus, Denmark as a simple test in which the aggregation, porosity and root growth of a spadeful of soil are integrated into a single score – a structural indicator. The indicator is assessed from a key containing photographs and traffic-light grading of quality on a laminated field chart that allows users to score their soil quickly.

The research was incorporated into practice guidelines for the Scottish Government document The Farm Soils Plan (used to help compliance with the EU requirement for Good Agricultural and Environmental Condition) and contributed to the report The State of Scotland’s Soil (SoS). The Farm Soils Plan was distributed to 10,000 farmers within the UK and is on the Scottish Government web site. The SoS report has been used as evidence to support further thinking on soils, which has in turn influenced UK policy. The main impacts of SoS are tied in with other drivers such as Scottish Soil Framework, Land Use Strategy and Rural Diffuse Pollution Plan for Scotland.

Reduction of soil structure has an immediate economic impact at farm level because a decrease in soil quality decreases crop yield. A decrease in structural quality as a result of compaction decreases grain yield by, typically, 16% [5.4]. If each of 1000 farms with substandard soil structure was improved by one VESS unit of soil structural quality then wheat yield would increase by 28 tonnes, a potential increase in revenue of £4,500 per farm, £4.5M annually overall (these figures are based on an average sized farm in the UK of 60 hectares with one third of the soil assumed to be in sub-standard physical condition and an average wheat yield of 7 t/ha. The structural improvement cost is estimated to be £50/h).